JP6341144B2 - Vehicle collision detection device - Google Patents

Description

  The present invention relates to a vehicle collision detection device that detects a collision of a pedestrian or the like with a vehicle.

  There has been a conventional technology related to a vehicle collision detection device that provides a shock absorber behind the bumper cover, disposes a detection tube between the shock absorber and the cross member, and detects a pedestrian collision with the front end of the vehicle ( For example, see Patent Document 1). The collision detection device according to the related art is intended to enable detection of a collision with a wide range of parts in the bumper cover, and when a pressure exceeding a threshold value is generated in the detection tube, the bumper cover is applied to the bumper cover. A pedestrian collision has been detected.

Special table 2014-505629 gazette

However, in the above-described conventional collision detection device for a vehicle, in order to satisfy the redundancy of collision determination, a pair of pressure sensors are provided at both ends of the detection tube, and the vehicle is detected based on the detection value by the pressure sensor. A collision is detected. Therefore, it is necessary to attach two pressure sensors in the vehicle, which complicates the manufacturing process of the vehicle collision detection device and increases the manufacturing cost. On the other hand, if only one pressure sensor is connected to the detection tube, the redundancy of collision determination cannot be satisfied, and it cannot be accurately detected that a collision has occurred. There was a problem.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle collision detection device that can accurately detect that a vehicle collision has occurred.

  In order to solve the above-mentioned problem, the invention of the vehicle collision detection device according to claim 1 is arranged to extend in the vehicle width direction at the front portion (21) of the vehicle (VE) and is deformed by the collision of the vehicle. A hollow member (31) having flexibility and having a pressure detection space (31a) therein, a first electrode (34, 38) attached to the front outer peripheral surface (31b) of the hollow member, and a rear outer peripheral surface (31c) ) Attached to the second electrode (35, 39), the first deformation detector (33, 62) for determining the deformation of the hollow member by detecting the pressure (Pdet) in the pressure detection space, An electric signal (Idet) is formed according to the distance between the first electrode and the second electrode, and the second deformation detector (63, 64, 71) that determines the deformation of the hollow member based on the formed electric signal. ) And the first deformation detector Based on the deformation of the empty member and the deformation of the hollow member determined by the second deformation detector, the occurrence of a collision that requires the operation of the protective device (5) that protects the collision object (OB, BH) is detected. A collision determination unit (67).

According to this configuration, the first deformation detection unit that determines the deformation of the hollow member by detecting the pressure in the pressure detection space and the distance between the first electrode and the second electrode are formed. And a second deformation detector that determines the deformation of the hollow member based on the electrical signal. Then, based on the deformation of the hollow member determined by the first deformation detection unit and the deformation of the hollow member determined by the second deformation detection unit, the occurrence of a collision that requires the operation of a protection device that protects the collision object Is provided with a collision determination unit. Thereby, the redundancy of collision determination is satisfied, and it is possible to accurately detect that a collision with the vehicle has occurred.
In addition, the deformation of the hollow member can be determined by the second deformation detection unit simply by attaching the first electrode and the second electrode to the outer peripheral surface of the hollow member. Accordingly, the vehicle collision detection device can be easily manufactured and reduced in cost.
The vehicle collision detection apparatus according to the present invention is intended not only for pedestrian collisions but also for all collision detections for vehicles.

The top view of the vehicle with which the pedestrian protection system by Embodiment 1 of this invention was attached. II-II sectional view of FIG. Schematic cross section when the pressure chamber is cut horizontally Block diagram showing the configuration of the pedestrian protection system 4 is a circuit diagram showing a state in which the impedance detection circuit shown in FIG. 4 is connected to the front conductor plate and the rear conductor plate. Sectional drawing showing the state where the impact by the collision was applied to the pressure chamber shown in FIG. Schematic vehicle plan view showing the case where a pedestrian collides with the left and right center of the front bumper Schematic vehicle plan view showing the case where a pedestrian collides with the left end of the front bumper The figure which showed the control flowchart of a pedestrian protection system Typical sectional drawing at the time of cutting horizontally the pressure chamber by the 1st modification of Embodiment 1 Schematic sectional view when the pressure chamber according to the second modification of the first embodiment is cut horizontally The circuit diagram which showed the state which connected the impedance detection circuit between the adjacent front conductor plates shown in FIG. Sectional drawing when the pressure chamber according to the second embodiment is cut horizontally Top view of the pressure chamber shown in FIG. XIIIB-XIIIB sectional view of FIG. 13A FIG. 12 is a bottom view of the pressure chamber shown in FIG. Sectional drawing showing the state where the impact by the collision was added with respect to the pressure chamber shown to FIG. 13B FIG. 13C is a bottom view showing a state in which an impact due to a collision is applied to the pressure chamber shown in FIG. 13C. The top view of the plane coil which is a modification of the inductor shown to FIG. 13A The figure showing the side view of the planar coil shown in FIG. 15A Plan view of another planar coil The figure showing the side view of the planar coil shown in FIG. 16A

<Configuration of Embodiment 1>
A pedestrian protection system 1 (corresponding to a vehicle collision detection device) according to Embodiment 1 of the present invention will be described with reference to FIGS. In each figure, the direction indication indicates the direction with respect to the vehicle VE. For example, the indication “front” indicates that the direction of the arrow corresponds to the front of the vehicle VE. 3 and 6, a pressure introduction tube 32 and a pressure sensor 33 described later are omitted. The following description focuses on pedestrian collision with the vehicle VE, but the vehicle collision detection device according to the present invention is intended for all collision detection with respect to the vehicle VE, not just pedestrian collision.

(Overall configuration of pedestrian protection system 1)
As shown in FIG. 1, a front bumper 21 (corresponding to a front portion of the vehicle) is attached to the front end portion of the vehicle VE. The front bumper 21 extends in the left-right direction (vehicle width direction), and includes a bumper cover 22 and a bumper absorber 23. The bumper cover 22 is formed of a synthetic resin material, and forms a design surface in the front portion of the vehicle VE. The bumper absorber 23 is provided behind the bumper cover 22 as a shock absorber when a collision occurs in the front portion of the vehicle VE. The bumper absorber 23 is made of a foamed resin such as foamed polypropylene, for example.

  The bumper absorber 23 is attached to the front surface 24a of the bumper reinforcement 24 at the rear end surface 23a. The bumper reinforcement 24 is a strength member that is formed hollow with a metal material such as an aluminum alloy, and extends in the vehicle width direction. The bumper reinforcement 24 is fixed to front ends of a pair of left and right side members 25R and 25L extending in the front-rear direction. The body unit 2 is formed by the front bumper 21, the bumper reinforcement 24, and the side members 25R and 25L described above.

As shown in FIG. 2, a pressure chamber 31 (corresponding to a hollow member) extending in the vehicle width direction is disposed on the upper end surface 23b of the bumper absorber 23 described above. The pressure chamber 31 is made of low-density polyethylene that is an insulator, and has the flexibility to be deformed by the collision of the vehicle VE. The pressure chamber 31 has a pressure detection space 31a therein, and air is sealed in the pressure detection space 31a.
A pair of pressure introducing tubes 32 communicating with the pressure detection space 31 a is attached to the pressure chamber 31. The pressure introducing tube 32 is connected to both ends of the pressure chamber 31 in the longitudinal direction. A pressure sensor 33 (corresponding to a first deformation detection unit) is connected to the end of each pressure introduction tube 32 on the side not connected to the pressure chamber 31. As the pressure sensor 33, a semiconductor strain gauge pressure sensor, a capacitance pressure sensor, or another pressure sensor is used. The pressure sensor 33 detects the pressure Pdet of air in the pressure detection space 31a (corresponding to the pressure in the pressure detection space, hereinafter referred to as a pressure detection value Pdet). The pressure sensor 33 may be provided only at one end of the pressure chamber 31.

  As shown in FIG. 2, the cross section of the pressure chamber 31 is formed in a substantially rectangular shape, and a front conductor plate 34 (corresponding to the first electrode) is attached to the front outer peripheral surface 31b with an adhesive. . A rear conductor plate 35 (corresponding to the second electrode) is stuck to the rear outer peripheral surface 31c of the pressure chamber 31 with an adhesive. The front conductor plate 34 and the rear conductor plate 35 are each formed of a plate material having good conductivity such as copper or iron. The front conductor plate 34 and the rear conductor plate 35 may be attached to the pressure chamber 31 by heat welding or insert molding.

A plurality of front conductor plates 34 are provided on the front outer peripheral surface 31b of the pressure chamber 31 so as to be aligned in the vehicle width direction (shown in FIG. 3). Further, the rear conductor plate 35 is continuously formed on the rear outer peripheral surface 31 c of the pressure chamber 31. On the other hand, the front conductor plate 34 is formed continuously on the front outer peripheral surface 31b of the pressure chamber 31, and a plurality of rear conductor plates 35 are provided on the rear outer peripheral surface 31 so as to be aligned in the vehicle width direction. Also good. A plurality of both the front conductor plate 34 and the rear conductor plate 35 may be provided so as to be arranged in the vehicle width direction on the front outer peripheral surface 31b or the rear outer peripheral surface 31, respectively. In this case, the front conductor plate 34 and the rear conductor plate 35 are disposed so as to face each other. Hereinafter, the front conductor plate 34 and the rear conductor plate 35 are collectively referred to as conductor plates 34 and 35. The chamber structure 3 is formed by the pressure chamber 31, the pressure introducing tube 32, the pressure sensor 33, and the conductor plates 34 and 35 described above.
As shown in FIG. 3, a plurality of capacitors C1, C2, C3, and C4 are formed by the front conductor plate 34 and the rear conductor plate 35 facing each other. Hereinafter, the capacitors C1, C2, C3, and C4 are collectively referred to as capacitors C1 to C4.

Returning to FIG. 1, the speed sensor 4 is attached to a wheel or a transmission (not shown) of the vehicle VE, and detects a traveling speed Vdet (hereinafter referred to as a vehicle speed detection value Vdet) of the vehicle VE.
The cowl airbag device 51 included in the pedestrian protection device 5 (corresponding to the protection device) is configured to cover the bag from the engine hood HE shown in FIG. 1 to the lower portion of the front window WF when a pedestrian collides with the front bumper 21. Deploy and protect the colliding pedestrian.
A pop-up hood 52 is also included in the pedestrian protection device 5. The pop-up hood 52 raises the rear end of the engine hood HE when a pedestrian collides with the front bumper 21. Thereby, the pop-up hood 52 serves as a buffer member, prevents the pedestrian from colliding with a rigid member such as an engine, and protects the colliding pedestrian.

(Configuration of pedestrian protection ECU 6)
In the vehicle VE, a pedestrian protection ECU 6 is mounted on a floor tunnel in front of the driver's seat (not shown). The pedestrian protection ECU 6 is a control device formed by an input / output device (not shown), CPU, RAM, and the like. As shown in FIG. 4, the pressure sensor 33, the capacitors C1 to C4, the speed sensor 4, the cowl airbag device 51, and the pop-up hood 52 described above are connected to the pedestrian protection ECU 6 by communication lines.
The pedestrian protection ECU 6 includes a vehicle speed determination unit 61, a main determination unit 62, an impedance detection circuit 63, a safing determination unit 64, a collision position detection unit 65, a threshold setting unit 66, a first AND circuit 67, a second AND circuit 68, and a protection device. A driver 69 is included.

  The vehicle speed determination unit 61 is connected to the speed sensor 4, and determines whether the vehicle speed detection value Vdet by the speed sensor 4 is equal to or higher than a predetermined first vehicle speed threshold Vth1 and equal to or lower than a predetermined second vehicle speed threshold Vth2. To do. The vehicle speed determination unit 61 outputs a high (H) signal when the vehicle speed detection value Vdet is equal to or higher than the first vehicle speed threshold Vth1 and equal to or lower than the second vehicle speed threshold Vth2.

The main determination unit 62 (first deformation detection unit) is connected to the pressure sensor 33 and the speed sensor 4. The main determination unit 62 calculates an effective mass M (corresponding to a predetermined physical quantity) from the pressure detection value Pdet by the pressure sensor 33, and the effective mass M corresponds to a predetermined effective mass threshold Mth or more (corresponding to a predetermined collision threshold or more). It is determined whether or not. The main determination unit 62 determines the deformation of the pressure chamber 31 and outputs an H signal when the effective mass M is equal to or greater than the effective mass threshold Mth.
The effective mass M refers to a mass calculated using the relationship between momentum and impulse using the pressure detection value Pdet at the time of collision. When a collision between the vehicle VE and the object OB (shown in FIG. 6) occurs, the pressure detection value Pdet by the pressure sensor 33 is different from that of the pedestrian in the collision object having a mass different from that of the pedestrian. For this reason, by setting a threshold value between the effective mass M of the human body and the assumed effective mass M of another collision object, it is possible to classify the types of the collision object. This effective mass M is calculated by dividing the interval integral value of the pressure detection value Pdet by the pressure sensor 33 at a predetermined time by the vehicle speed detection value Vdet, as shown in the following equation.
M = {∫Pdet (t) dt} / Vdet
As another method for calculating the effective mass M, it is possible to calculate using the equation E = {M (Vdet) ² } / 2 representing the kinetic energy E of the colliding object. In this case, the effective mass M is calculated by M = 2 × E / (Vdet) ² .

As shown in FIG. 5, the impedance detection circuit 63 (corresponding to the second deformation detection unit) is formed by combining the oscillation circuit and the current detection circuit, and the capacitors C1 to C4 (conductor plate) described above. 34, 35) are connected. The impedance detection circuit 63 shown in FIG. 5 is formed for each of the connected capacitors C1 to C4 (a total of four), and each impedance detection circuit 63 is connected to each front conductor plate 34. The impedance detection circuit 63 is connected in parallel to the high-frequency voltage source 63a, the amplifier 63b connected to the high-frequency voltage source 63a, the detection resistor 63c connected between the amplifier 63b and the capacitors C1 to C4, and the detection resistor 63c. It is formed by a volt meter 63d.
Each of the capacitors C1 to C4 has a capacitance CC corresponding to the distance between the front conductor plate 34 and the rear conductor plate 35. The capacity CC is calculated by the following formula.
CC = ε ₀ × ε _a × (S / d)
Where S is the area of the front conductor plate 34, d is the distance between the front conductor plate 34 and the rear conductor plate 35, ε ₀ is the dielectric constant of vacuum, and ε _a is the relative dielectric constant of air in the pressure detection space 31a. And

In the impedance detection circuit 63, a detection current Idet (corresponding to an electrical signal, hereinafter referred to as a current detection value Idet) flows through the detection resistor 63c according to the capacitance CC of each of the capacitors C1 to C4. The current detection value Idet is obtained from the voltage across the detection resistor 63c detected by the voltmeter 63d.
As shown in FIG. 6, when an object OB (corresponding to a collision object) collides with the front bumper 21 of the vehicle VE, the pressure detection space 31a of the pressure chamber 31 is compressed and deformed, and the pressure detection in the pressure detection space 31a is detected. The value Pdet increases. At the same time, the distance d between the front conductor plate 34 and the rear conductor plate 35 of the capacitor C2 located at the collision site decreases, and the capacitance CC of the capacitor C2 increases. Therefore, in the impedance detection circuit 63 connected to the capacitor C2, the current detection value Idet also increases. That is, the impedance detection circuit 63 forms a current detection value Idet according to the capacitance CC that changes according to the distance d between the front conductor plate 34 and the rear conductor plate 35.

  The safing determination unit 64 (second deformation detection unit) is connected to the impedance detection circuit 63 and detects the deformation of the pressure chamber 31 based on the current detection value Idet formed by the impedance detection circuit 63. . The safing determination unit 64 determines whether or not the current detection value Idet is equal to or greater than a predetermined current threshold Ith (corresponds to a predetermined electrical threshold or more). The safing determination unit 64 determines the deformation of the pressure chamber 31 when the capacitance CC of any of the capacitors C1 to C4 increases and the detected current value Idet flowing through the impedance detection circuit 63 becomes equal to or greater than the current threshold value Ith. , H signal is output.

  The collision position detection unit 65 is connected to the impedance detection circuit 63 and is based on a current detection value Idet formed according to the distance d between the front conductor plate 34 and the rear conductor plate 35 provided at each position. Thus, the position Y (shown in FIG. 6) in the vehicle width direction where the collision has occurred is detected. That is, the collision position detection unit 65 detects that there is a collision at the vehicle width direction position Y provided with the capacitors C1 to C4 connected to the impedance detection circuit 63 in which the current detection value Idet is increased. For example, the collision position detection unit 65 has a collision at a vehicle width direction position Y provided with capacitors C1 to C4 (C2 in FIG. 6) connected to the impedance detection circuit 63 in which the current detection value Idet has increased most. Detect that.

The threshold setting unit 66 is connected to the collision position detection unit 65 and the main determination unit 62. The threshold setting unit 66 changes (sets) the effective mass threshold Mth described above based on the position Y in the vehicle width direction of the vehicle VE where the pedestrian collision has been detected, which is detected by the collision position detection unit 65, and the main determination unit To 62.
In general, when a pedestrian BH (corresponding to a collision object) collides with the vicinity of the left and right end portions of the front bumper 21 as compared to the case where the pedestrian BH collides with the vicinity of the central portion of the front bumper 21 (see FIG. 7A) ( In FIG. 7B, the pressure detection value Pdet in the pressure detection space 31a is lower even if the impact applied to the vehicle VE is the same. Therefore, the threshold setting unit 66 sets the effective mass threshold Mth lower when the pedestrian BH collides with the vicinity of the left and right end portions of the front bumper 21 than when the pedestrian BH collides with the vicinity of the central portion of the front bumper 21 in the left and right direction. ing.

  A pair of input terminals of the first AND circuit 67 (collision determination unit) is connected to the main determination unit 62 and the safing determination unit 64. In the first AND circuit 67, the main determination unit 62 determines that the effective mass M is greater than or equal to the effective mass threshold Mth, and the safing determination unit 64 determines that the current detection value Idet is greater than or equal to the current threshold Ith. In the case of an error, the H signal is output. In this case, the occurrence of a collision that requires the operation of the pedestrian protection device 5 that protects the pedestrian BH is detected.

A pair of input terminals of the second AND circuit 68 are connected to the vehicle speed determination unit 61 and the output terminals of the first AND circuit 67. In the second AND circuit 68, the vehicle speed determination unit 61 determines that the vehicle speed detection value Vdet is equal to or higher than the first vehicle speed threshold value Vth 1 and equal to or lower than the second vehicle speed threshold value Vth 2, and further, an H signal is output from the first AND circuit 67. If it is output, an H signal is output.
The protective device driver 69 is connected to the output terminal of the second AND circuit 68 and the pedestrian protective device 5, and when the H signal is output from the second AND circuit 68, the cowl airbag device 51 or the pop-up hood 52 is connected. Operate.

(Control method of pedestrian protection system 1)
Hereinafter, based on FIG. 8, the control method of the pedestrian protection system 1 by pedestrian protection ECU6 is demonstrated. First, the vehicle speed detection value Vdet of the vehicle VE is input from the speed sensor 4 to the vehicle speed determination unit 61 (step S101). Next, the vehicle speed determination unit 61 determines whether or not the vehicle speed detection value Vdet is greater than or equal to the first vehicle speed threshold value Vth1 and less than or equal to the second vehicle speed threshold value Vth2 (step S102). When it is determined that the vehicle speed detection value Vdet is less than the first vehicle speed threshold value Vth1 or exceeds the second vehicle speed threshold value Vth2, this control flow ends. When it is determined that the vehicle speed detection value Vdet is equal to or greater than the first vehicle speed threshold Vth1 and equal to or less than the second vehicle speed threshold Vth2, the pressure detection value Pdet is input from the pressure sensor 33 to the main determination unit 62. (Step S103). Thereafter, the main determination unit 62 calculates the effective mass M from the pressure detection value Pdet and the vehicle speed detection value Vdet (step S104).

  If it is determined in step S102 that the vehicle speed detection value Vdet is equal to or higher than the first vehicle speed threshold Vth1 and equal to or lower than the second vehicle speed threshold Vth2, the impedance detection circuit 63 sends a collision position detection unit 65 to the collision position detection unit 65. On the other hand, the current detection value Idet is input (step S105). The collision position detection unit 65 calculates the collision position Y based on the current detection value Idet detected by each impedance detection circuit 63, and transmits it to the threshold setting unit 66 (step S106). The threshold setting unit 66 sets an effective mass threshold Mth based on the collision position Y, and transmits the effective mass threshold Mth to the main determination unit 62 (step S107). In the main determination unit 62, it is determined whether or not the calculated effective mass M is equal to or greater than the effective mass threshold Mth (step S108). When the effective mass M is equal to or greater than the effective mass threshold Mth, the main determination unit 62 determines that the pressure detection space 31a has been deformed, and transmits an H signal to the first AND circuit 67. When the effective mass M is less than the effective mass threshold Mth, the main determination unit 62 transmits a low (L) signal to the first AND circuit 67, and this control flow ends.

  From each impedance detection circuit 63, the current detection value Idet is also input to the safing determination unit 64 (step S109). The safing determination unit 64 determines whether each input current detection value Idet is equal to or greater than the current threshold Ith (step S110). When any current detection value Idet is equal to or greater than the current threshold Ith, the safing determination unit 64 detects that the pressure detection space 31a is deformed and the capacitance of any one of the capacitors C1 to C4 is increased. The H signal is transmitted to the first AND circuit 67. If the current detection values Idet of all the impedance detection circuits 63 are less than the current threshold value Ith, the safing determination unit 64 transmits an L signal to the first AND circuit 67 and ends this control flow. When the effective mass M is equal to or greater than the effective mass threshold Mth and the current detection value Idet of any impedance detection circuit 63 is equal to or greater than the current threshold Ith, a pedestrian collision with the front bumper 21 has occurred. Is determined (step S111). Thereby, the pedestrian protection apparatus 5 is operated (step S112).

<Effect of Embodiment 1>
According to this embodiment, the main determination part 62 which determines the deformation | transformation of the pressure chamber 31 by detecting the pressure in the pressure detection space 31a is provided. In addition, a safing determination unit 64 that determines the deformation of the pressure chamber 31 based on the detected current value Idet formed according to the distance d between the front conductor plate 34 and the rear conductor plate 35 is provided. Furthermore, the pedestrian protection ECU 6 detects the occurrence of a collision based on the deformation of the pressure chamber 31 detected by the main determination unit 62 and the deformation of the pressure chamber 31 detected by the safing determination unit 64. . Thereby, the redundancy of collision determination is satisfied, and it is possible to accurately detect that a collision with the vehicle VE has occurred.
Further, the deformation of the pressure chamber 31 can be determined by the safing determination unit 64 only by attaching the front conductor plate 34 and the rear conductor plate 35 to the front outer peripheral surface 31b or the rear outer peripheral surface 31c of the pressure chamber 31. it can. Therefore, it is not necessary to complicate the manufacturing process, the manufacturing is easy, and the low-cost pedestrian protection system 1 can be obtained.

  The main determination unit 62 determines that the pressure chamber 31 has been deformed when the effective mass M detected based on the pressure in the pressure detection space 31a is equal to or greater than the effective mass threshold Mth. Further, a collision for detecting a position Y in the vehicle width direction where the collision occurs based on a current detection value Idet formed according to a distance between the front conductor plate 34 and the rear conductor plate 35 provided at each position. A position detector 65 is provided. Furthermore, a threshold value setting unit 66 that sets the effective mass threshold value Mth based on the position Y in the vehicle width direction where the collision detected by the collision position detection unit 65 occurs is provided. Thereby, the detection sensitivity of the pedestrian collision can be changed according to the position Y in the vehicle width direction of the vehicle VE where the pedestrian collision has occurred. Therefore, the occurrence of a pedestrian collision can be accurately determined regardless of the position Y in the vehicle width direction of the vehicle VE where the pedestrian collision has occurred.

The pedestrian protection ECU 6 deforms the pressure detection space 31a when the effective mass M is equal to or greater than the effective mass threshold Mth and the current detection value Idet formed by the impedance detection circuit 63 is equal to or greater than the current threshold Ith. Then, it is detected that a collision has occurred in the vehicle VE. Thereby, the deformation of the pressure detection space 31a of the pressure chamber 31 can be determined with certainty, the redundancy of collision determination can be satisfied, and the detection accuracy can be improved.
Further, the capacitors C1 to C4 are formed by the conductor plates 34 and 35 facing each other, and the safing determination unit 64 is based on the current detection value Idet formed according to the capacitance CC of the capacitors C1 to C4. The deformation is determined. Thereby, the deformation | transformation of the pressure chamber 31 can be easily determined using the fall of the capacity | capacitance CC of the capacitors C1-C4 resulting from the reduction | decrease of the distance between the front conductor board 34 and the back conductor board 35. FIG. Further, since it is only necessary to detect the current detection value Idet that changes according to the capacitance CC of the capacitors C1 to C4 in order to determine the deformation of the pressure chamber 31, it is possible to make the impedance detection circuit 63 a simple circuit configuration. it can.

<Configuration of First Modification of First Embodiment>
A chamber structure 3A according to a first modification of the first embodiment will be described with reference to FIG. In FIG. 9, the pressure introducing tube 32 and the pressure sensor 33 are omitted. The chamber structure 3A according to the present modification is different from the chamber structure 3 according to the first embodiment in that the front conductor plate 34 and the front guard electrode 37f (corresponding to the conductive member) via the insulating sheet 36f (corresponding to the insulating member). ) Is different. Another difference is that a rear guard electrode 37r (corresponding to a conductive member) is attached to the rear conductor plate 35 via an insulating sheet 36r (corresponding to an insulating member). Other configurations are the same as those of the chamber structure 3 according to the first embodiment. Of the conductor plates 34 and 35, the front guard plate 37f may be attached to only the front conductor plate 34 via the insulating sheet 36f, or only the rear conductor plate 35 may be attached to the rear side via the insulating sheet 36r. A guard electrode 37r may be attached. Hereinafter, the insulating sheet 36f and the insulating sheet 36r are collectively referred to as insulating sheets 36f and 36r, and the front guard electrode 37f and the rear guard electrode 37r are collectively referred to as guard electrodes 37f and 37r.

The insulating sheets 36f and 36r are formed in a flat plate shape from a PET (Polyethylene terephthalate) film or a PEN (Polyethylene naphthalate) film. The guard electrodes 37f and 37r are formed in a plate shape from a metal material having good conductivity such as copper or iron. The insulating sheets 36f and 36r and the guard electrodes 37f and 37r are fixed to the conductor plates 34 and 35 with an adhesive or the like.
As described above, the guard electrodes 37f and 37r are attached to the conductor plates 34 and 35 in an insulated state. Thereby, even if a capacity (indicated by Cns in FIG. 9) is generated between the other member FR other than the chamber structure 3A and the guard electrodes 37f and 37r on the vehicle VE, the other member FR Capacitive coupling between the conductor plates 34 and 35 can be prevented.

<Operational effects of the first modification>
According to this modification, the guard electrodes 37f and 37r are attached to the conductor plates 34 and 35 via the insulating sheets 36f and 36r, respectively, and capacitive coupling between the other member FR and the conductor plates 34 and 35 is prevented. doing. Thereby, in the capacitors C1 to C4, the capacitance CC corresponding to the distance between the front conductor plate 34 and the rear conductor plate 35 can be generated with high accuracy. Therefore, the deformation of the pressure chamber 31 can be accurately determined based on the current detection value Idet.

<Configuration of Second Modification of First Embodiment>
A pedestrian protection system 1 according to a second modification of the first embodiment will be described with reference to FIGS. 10 and 11. In FIG. 10, the pressure introducing tube 32 and the pressure sensor 33 are omitted. The pedestrian protection ECU 6 according to the present modification includes an impedance detection circuit 70 (corresponding to a moisture detection unit) similar to the impedance detection circuit 63 according to the first embodiment. As shown in FIG. 11, the impedance detection circuit 70 is formed by a configuration in which an oscillation circuit and a current detection circuit are combined. The impedance detection circuit 70 is connected to the adjacent front conductor plates 34 of the chamber structure 3. The impedance detection circuit 70 shown in FIG. 11 is formed for each adjacent front conductor plate 34 (three in total), and each impedance detection circuit 70 is connected to both adjacent front conductor plates 34. . Similar to the impedance detection circuit 63, the impedance detection circuit 70 includes a high frequency voltage source 70a, an amplifier 70b, a detection resistor 70c, and a voltmeter 70d.
As shown in FIG. 10, a capacitance Cw and a DC resistance component rw exist between the adjacent front conductor plates 34. Therefore, in the impedance detection circuit 70, the determination current Idw corresponding to the capacitance Cw and the DC resistance component rw between the adjacent front conductor plates 34 (corresponding to the first electrodes) flows through the detection resistor 70c. Then, the determination current Idw is obtained from the voltage across the detection resistor 70c detected by the voltmeter 70d.

Usually, the pressure chamber 31 is provided with an air hole (not shown) in order to keep the atmospheric pressure in the pressure chamber 31 the same as the atmosphere. Due to the air holes, moisture may enter the pressure chamber 31 and condensation may occur in the pressure chamber 31. As shown in FIG. 10, when the inside of the pressure chamber 31 is flooded or dew condensation DW occurs in the pressure chamber 31, the capacitance Cw between the adjacent front conductor plates 34 increases, The resistance component rw decreases. Therefore, in the impedance detection circuit 70 connected between the adjacent front conductor plates 34, the determination current Idw also changes. The impedance detection circuit 70 detects the capacitance Cw and the direct current resistance rw between the adjacent front conductor plates 34 through the determination current Idw, and detects the presence or absence of moisture in the pressure chamber 31 based on them. To do. When the presence of moisture in the pressure chamber 31 is detected, a warning is issued in the vehicle VE and the operation of the pedestrian protection system 1 is stopped.
A plurality of rear conductor plates 35 are provided, and the capacitance Cw and the direct current resistance rw between the adjacent rear conductor plates 35 (corresponding to the second electrodes) are detected, and based on them, the pressure chamber 31 is detected. The presence or absence of moisture in the inside may be detected.

<Operational effects of the second modification>
According to this modification, the impedance detection circuit 70 detects the capacitance Cw and the DC resistance component rw between the adjacent front conductor plates 34 through the determination current Idw. The presence or absence of moisture in the pressure chamber 31 is detected based on the detected capacitance Cw and the DC resistance component rw. Thereby, it is possible to prevent moisture in the pressure chamber 31 from blocking air holes formed in the pressure chamber 31. Therefore, the pressure in the pressure detection space 31a can always be accurately detected, and the pedestrian protection system 1 can be normally operated.

<Configuration of Embodiment 2>
Based on FIG. 12 thru | or FIG. 16B, the pedestrian protection system 1 by Embodiment 2 is demonstrated. In FIG. 12, the pressure introducing tube 32 and the pressure sensor 33 are omitted. In the chamber structure 3B according to the present embodiment, a plurality of inductors 38 (one side of the first electrode and the second electrode, corresponding to a coil, are provided on the front outer peripheral surface 31b of the pressure chamber 31 instead of the front conductor plate 34. ) Are mounted in line in the vehicle width direction. Each inductor 38 is formed by winding a conductive wire in a coil shape, and has a predetermined length in the axial direction (vertical direction in FIG. 13B). A continuous conductive plate 39 (corresponding to the other of the first electrode and the second electrode) extending in the vehicle width direction is attached to the rear outer peripheral surface 31c of the pressure chamber 31. The conductive plate 39 is formed of a plate material having good conductivity such as copper or iron. Unlike the case described above, a plurality of inductors 38 may be provided on the rear outer peripheral surface 31c of the pressure chamber 31, and the conductive plate 39 may be attached to the front outer peripheral surface 31b. Further, the conductive plate 39 may be formed of a plurality of conductive plates that face the inductor 38, respectively.

  The pedestrian protection ECU 6 according to the present embodiment includes an impedance detection circuit 71 (corresponding to a second deformation detection unit) similar to the impedance detection circuit 63 according to the first embodiment. The impedance detection circuit 71 is formed by a configuration combining an oscillation circuit and a current detection circuit, and each inductor 38 is connected (shown in FIG. 13A). The impedance detection circuit 71 is formed for each inductor 38 (a total of four) and is connected to each inductor 38. Each impedance detection circuit 71 detects an electrical signal formed according to the impedance of each connected inductor 38.

As shown in FIG. 13B, when a current having a predetermined frequency is applied by the impedance detection circuit 71, the inductor 38 generates a predetermined magnetic flux φ. Due to the magnetic flux φ formed by the inductor 38, an eddy current EC is generated in the conductive plate 39 (shown in FIG. 13C).
When a collision occurs in the front bumper 21 of the vehicle VE, the pressure detection space 31a of the pressure chamber 31 is compressed and deformed, the distance between the inductor 38 located at the collision site and the conductive plate 39 is decreased, and the magnetic flux φ is increased. (FIG. 14A is shown). As the magnetic flux φ is increased by the inductor 38, the eddy current EC in the conductive plate 39 also increases (shown in FIG. 14B). Thereby, the impedance of the inductor 38 is changed by mutual induction between the eddy current EC and the inductor 38. The impedance detection circuit 71 detects the deformation amount of the pressure chamber 31 based on an electrical signal formed according to the impedance of each inductor 38. A method for detecting the distance between the inductor 38 and the conductive plate 39 based on the impedance of the inductor 38 is known. For example, Japanese Patent Application Laid-Open No. 2002-90105 or Japanese Patent Application No. 2011-119114, which is a patent publication, discloses. It is disclosed.

The collision position detection unit 65 of the pedestrian protection ECU 6 is connected to the impedance detection circuit 71 as in the first embodiment. The collision position detection unit 65 detects the collision position Y of the pedestrian to the front bumper 21 based on an electrical signal formed according to the impedance of each inductor 38.
Further, the threshold setting unit 66 sets the effective mass threshold Mth based on the position Y in the vehicle width direction of the vehicle VE where the detected pedestrian collision has occurred.
Similarly to the first embodiment, when the vehicle VE satisfies a predetermined vehicle speed condition, the pedestrian protection ECU 6 has an effective mass M that is greater than or equal to the effective mass threshold Mth and the impedance of each inductor 38. If the electric signal formed in response is equal to or greater than (or less than) a predetermined threshold, it is determined that a collision has occurred in the vehicle VE. When it is determined that a collision has occurred in the vehicle VE, the pedestrian protection device 5 is activated.

Instead of the inductor 38, a planar coil 38A (corresponding to a first electrode and a coil) shown in FIGS. 15A and 15B may be attached to the front outer peripheral surface 31b of the pressure chamber 31. The planar coil 38A is formed by winding a conducting wire in a perfect circle on a plane.
Further, a planar coil 38B (corresponding to a first electrode and a coil) shown in FIGS. 16A and 16B may be attached to the front outer peripheral surface 31b of the pressure chamber 31. The planar coil 38B is formed by winding a conducting wire in a rectangular shape on a plane.
By attaching the planar coil 38A or the planar coil 38B to the front outer peripheral surface 31b of the pressure chamber 31, the length in the front-rear direction of the chamber structure 3B can be reduced.

<Effects of Second Embodiment>
According to this embodiment, the inductor 38 is attached to the front outer peripheral surface 31b of the pressure chamber 31, and the conductive plate 39 is attached to the rear outer peripheral surface 31c. The impedance detection circuit 71 determines the deformation of the pressure chamber 31 based on an electric signal formed according to the impedance of the inductor 38 when a current having a predetermined frequency is passed through the inductor 38. Thereby, the deformation of the pressure chamber 31 can be easily determined using the change in the impedance of the inductor 38 due to the decrease in the distance between the inductor 38 and the conductive plate 39. In addition, since it is only necessary to detect an electric signal formed according to the impedance of the inductor 38 in order to determine the deformation of the pressure chamber 31, the impedance detection circuit 71 can be made simple.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
In order to detect the occurrence of a pedestrian collision in the front bumper 21, instead of using the effective mass M, the pressure in the pressure detection space 31a may be compared with a predetermined pressure threshold, or the pressure in the pressure detection space 31a. The load calculated based on the above may be compared with a predetermined load threshold. Alternatively, the pressure calculated based on the pressure in the pressure detection space 31a or the pressure in the pressure detection space 31a may be used together with the effective mass M.

  In the drawings, 1 is a pedestrian protection system (vehicle collision detection device), 5 is a pedestrian protection device (protection device), 21 is a front bumper (front part of the vehicle), 31 is a pressure chamber (hollow member), and 31a is pressure. Detection space, 31b is a front outer peripheral surface, 31c is a rear outer peripheral surface, 33 is a pressure sensor (first deformation detector), 34 is a front conductor plate (first electrode, conductor plate), and 35 is a rear conductor plate (second electrode). , Conductor plate), 36f and 36r are insulating sheets (insulating members), 37f is a front guard electrode (conductive member), 37r is a rear guard electrode (conductive member), and 38 is an inductor (first electrode and second electrode). 38A, 38B is a planar coil (one side of the first electrode and the second electrode, coil), 39 is a conductive plate (the other side of the first electrode and the second electrode), 62 is Main determination unit (first deformation detection Part), 63 and 71 are impedance detection circuits (second deformation detection part), 64 is a safing determination part (second deformation detection part), 65 is a collision position detection part, 66 is a threshold setting part, and 67 is a first AND circuit. (Collision determination unit), 70 is an impedance detection circuit (moisture detection unit), BH is a pedestrian (collision), C1, C2, C3, and C4 are capacitors, CC is a capacitor capacity, Idet is a current detection value (electrical signal) ), Ith is an electric current threshold (electrical threshold), M is an effective mass (predetermined physical quantity), Mth is an effective mass threshold (collision threshold), OB is an object (collision), Pdet is a pressure detection value (in the pressure detection space) VE represents the vehicle, and Y represents the position in the vehicle width direction where the collision occurred.

Claims (7)

A hollow member (31) disposed in a front portion (21) of the vehicle (VE) so as to extend in the vehicle width direction, having a flexibility to be deformed by a collision of the vehicle, and having a pressure detection space (31a) therein; ,
A first electrode (34, 38) attached to the front outer peripheral surface (31b) of the hollow member and a second electrode (35, 39) attached to the rear outer peripheral surface (31c);
A first deformation detector (33, 62) that determines the deformation of the hollow member by detecting the pressure (Pdet) in the pressure detection space;
A second deformation detection unit that forms an electric signal (Idet) according to a distance between the first electrode and the second electrode, and determines deformation of the hollow member based on the formed electric signal. 63, 64, 71),
A protective device (5) that protects the collision object (OB, BH) based on the deformation of the hollow member determined by the first deformation detector and the deformation of the hollow member determined by the second deformation detector. A collision determination unit (67) for detecting the occurrence of a collision requiring the operation of
A vehicle collision detection device (1). The first deformation detector is
Determining a deformation of the hollow member when a predetermined physical quantity (M) detected based on a pressure in the pressure detection space is equal to or greater than a predetermined collision threshold (Mth);
At least one of the first electrode and the second electrode (34, 38) is provided in plural on the front outer peripheral surface or the rear outer peripheral surface of the hollow member so as to be aligned in the vehicle width direction,
A collision position for detecting a position (Y) in the vehicle width direction where the collision has occurred based on the electrical signal formed according to the distance between the first electrode and the second electrode provided at each position A detector (65);
A threshold setting unit (66) for setting the collision threshold based on the position in the vehicle width direction where the collision detected by the collision position detection unit has occurred;
The vehicle collision detection device according to claim 1, further comprising: The collision determination unit
The occurrence of a collision is detected when the physical quantity is equal to or greater than the collision threshold and the electrical signal formed by the second deformation detection unit is equal to or greater than a predetermined electrical threshold (Ith). Vehicle collision detection device. The first electrode and the second electrode are formed by conductor plates (34, 35), respectively, so that capacitors (C1, C2, C3, C4) are formed by the first electrode and the second electrode facing each other. Formed,
The second deformation detection unit includes:
The vehicle collision detection device according to any one of claims 1 to 3, wherein the deformation of the hollow member is determined based on the electric signal formed according to the capacitance (CC) of the capacitor.   The vehicle collision detection device according to claim 4, wherein a conductive member (37f, 37r) is attached to at least one of the first electrode and the second electrode via an insulating member (36f, 36r).   Moisture detection that detects the capacitance between the adjacent first electrodes or the capacitance between the adjacent second electrodes, and detects the presence or absence of moisture in the hollow member based on the detected capacitance The vehicle collision detection device according to claim 4, further comprising a portion (70). One side of the first electrode and the second electrode is formed by a coil (38, 38A, 38B), and the other side is formed by a conductive plate (39).
The second deformation detector (71)
The deformation | transformation of the said hollow member is determined based on the said electrical signal formed according to the impedance of the said coil when the electric current which has a predetermined frequency is sent through the said coil. The vehicle collision detection device according to claim 1.

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